Obesity and less severe overweight conditions are a significant cause of morbidity and mortality in humans. High body weight is a risk factor for many diseases and disorders, particularly when fat comprises a high percentage of body weight. For example, incidence of each of type II diabetes, cholelithiasis, hypertension, and coronary heart disease is much greater in obese humans than in non-obese humans. Other diseases associated with obesity include arthritis, various cancers (e.g., breast, colorectal, and endometrial cancers), renal failure, liver disease, chronic pain (e.g., lower back pain), sleep apnea, stroke, and urinary incontinence.
In addition to medical risks attributable to large amounts of body fat, fat accumulation is considered by many to be cosmetically undesirable as well. Likely attributable to popular notions regarding desirable body size and shape, many people are afflicted by psychological disruptions that might be alleviated if body fat were reduced or more easily controlled.
Body mass index (BMI) is a common measurement used to diagnose overweight and obesity. BMI is calculated by dividing an individual's weight in kilograms by the square of the individual's height in meters. Weight classifications have been developed by the National Heart, Lung, and Blood Institute (NHLBI), and these classifications can be used to divide the population into six groups, based on BMI, as follows:
BMI (body weight in kilograms perClassificationsquare of height in meters)Underweight<18.5Normal18.5 to <25.0Overweight25.0 to <30.0Obesity Class 130.0 to <35.0Obesity Class 235.0 to <40.0Obesity Class 3≧40.0
Using the NHLBI criteria, 17.9% of the U.S. population was obese (obesity class 1, 2, or 3) in 1998, corresponding to more than 45 million individuals. Estimates of medical costs attributable to obesity and related conditions were about $100 billion in the United States in 1999 (American Obesity Association report, 1999, “Costs of Obesity”). Furthermore, significant costs are associated with weight loss programs undertaken by individuals (e.g., about $33 billion per year in the U.S. in the late 1990s; 1998 Federal Trade Commission Report, “Consumer Weight Loss Products and Programs”).
Clearly, obesity and overweight are problems of critical importance. Significant economic, medical, and psychological gains could be achieved if compositions and methods could be developed that allow people to lose weight.
Prior art weight loss methods and compositions have not been widely successful. Current treatments for obesity and overweight include diet, pharmaceutical agents, surgery, and herbal therapy. Dietary methods for inhibiting or reversing obesity and overweight have a very low long term benefit rate. Although some pharmaceutical agents (and combinations of agents) have exhibited the ability to reduce body weight, many of these agents have been withdrawn from markets owing to toxicity, lack of efficacy, or both. Surgical methods of treating obesity and overweight are costly, are sometimes accompanied by very serious complications, exhibit significant variation in outcome, and are not amenable for use in all patients. Herbal (and “nutraceutical”) compositions for weight loss are popular, but their efficacy is typically not demonstrated. Owing to their often unknown mechanism of action, the variability of their composition, and their lack of credible clinical data, herbal weight loss compositions are not suitable for widespread use in the population.
A critical need remains for compositions and methods that can be used to effect weight loss in humans. The present invention satisfies this need, at least in part, by providing such compositions and methods.